As is well known, there are many applications for cement and concrete in most areas of construction. Since cement sets very quickly once water is added, batches typically must be mixed on site. For very small amounts, there is no problem in using manual labor with trowel or shovel for the mixing and for relatively large amounts one can more economically purchase truckloads of mixture which are delivered to the site in cement trucks. However, for the amounts between these extremes, mixing cement is not an easy task since motorized devices for mixing the cement are not conveniently available.
It is known, for example, to provide a rotatable electric-motor-driven container having an opening which is positionable at an angle at which the container may be filled with cement mix and water and which may after mixing then be tilted for pouring into forms or for emptying the contents into other containers for carrying to the desired location at the site. Such devices typically can be rented at local tool rental outlets, but they must either be towed or disassembled before transporting and will conveniently fit only in a truck or van. These containers are awkward to use because of the height of the opening where the cement mix is put in. A typical total mixing time for 240 pounds of cement in these devices is about 15 minutes and the cleanup of these machines is both time-consuming and messy.
There are mixing devices available from the Exaco company which are represented as being useful for mixing cement. When a device such as the Exaco Mixer Model 140 is actually used for mixing a thick mixture such as e.g. ready mix concrete, there is essentially no control of the unit's entry points into the mix and the cement is thrown outward away from the paddles so that there is no cement near the center. The resulting composition of the cement mix has been found to be poor. The blades of the mixer simply slice through the mixture without blending it.
Other mixing devices are available from Jiffler. These devices are represented as being desirable for mixing of materials such as paints because no air is introduced into the mix. It is known that for the best quality cement, there must be air incorporated into the mix. Consequently this device has not been found suitable for the mixing of cement.